Forgot my email address—help!

So, here’s the situation... my mom dropped her phone in the water and it’s completely fried. 😢 It’s dead, though that isn't even the main issue since a new one is already on its way. The real headache is trying to log into her Google account. Since she’s older, she doesn't really care about this digital stuff the way we do, and she has absolutely no clue what her email address is—which, I should mention, I set up for her ages ago just so I could make her a Facebook account. If it weren't for that annoying Facebook requirement, I’d just create a brand new email for her and call it a day, but I’d rather not deal with the hassle of linking a new email to a new profile right now. I was wondering if there’s any way to track down that old address, maybe through Facebook? I remember back in the day you could search for an email in Google and it would pull up a link to a profile, but I never actually sent her any emails, so I guess that option is out...
Any bright ideas?

Should I use my cell number instead of an email on Facebook? Because once you log in, it should show your email address anyway.

William Palmer7 said:Should I use my cell number instead of an email on Facebook? Because once you log in, it should show your email address anyway.

Hmm... though I'm not entirely sure if they remember the password. 😁 Well, I managed to figure out which email is linked to the account through a bit of trial and error, so resetting the password via another email or a phone number should be pretty straightforward.
Thanks